The rotor hubs of wind turbines generally have special cutouts which are suitable for access of components or tools in order to transport these into the hub or nacelle or to exchange them. The rotor hub can be covered by a spinner in order to protect the rotor hub against environmental influences. A spinner is a housing which completely or partially encloses the rotor hub. The spinner improves the aerodynamic characteristics of the rotor and contributes to an aesthetic appearance of the wind turbine. A spinner furthermore offers the advantage that work can be carried out in its interior at considerable height even in poor weather.
For each rotor blade, the spinner has a rotor blade opening into which the rotor blade can be inserted during installation. Located between spinner and rotor blade is an annular gap which requires special sealing in order to protect the interior of the spinner against environmental influences. Otherwise, water running down on the rotor blade could, in particular, penetrate the interior of the spinner unhindered and damage the elements of the rotor hub which are located therein and are generally not specifically protected against environmental influences.
The mounting of the rotor blade on the rotor hub is usually carried out at considerable height and not always in calm conditions. In order to be able to guide the rotor blade through the rotor blade opening in the spinner onto the rotor hub in a secure and damage-free manner, however, the annular gap has to have a considerable width of, for example, approximately 160 mm. During subsequent operation of the wind turbine, moreover, a relative movement takes place between the rotor blade and the rotor blade opening in the spinner during adjustment of the blade pitch angle, which has to be taken into account in the sealing of the annular gap.
A cover profile for covering the annular gap is disclosed in printed publication CN 201739095 U. It has a central, conical section and two short circular-cylindrical sections adjoining it.
The cover profile disclosed in printed publication CN 201326508 Y has a cross section which is exactly the same but is divided into two semicircular segments.
A further cover profile, which is divided into two semi-circular segments, is disclosed in printed publication CN 202326034 U. In an exemplary embodiment, the segments are mounted in a manner in which they overlap each other.
The two printed publications WO 2011/012664 A2 and WO 2011/012683 A2 show a cover of the annular gap with two adjacently arranged cover rings. One of the cover rings is fastened on a spinner-like housing and the other is fastened on the rotor blade.
A wind turbine, in which two cover profiles interact to cover the annular gap, is disclosed in U.S. Pat. No. 7,745,951. A first cover profile is ring-shaped and fastened on the rotor blade. It has a conical section, beginning at the rotor blade, and a circular-cylindrical section adjoining it. The free end of the circular-cylindrical section engages in a type of annular groove which is formed on a second ring-shaped cover profile which is fastened at the rotor opening of the spinner. As a result, the penetration of water into the annular gap is to be prevented regardless of whether the water flows from the hub or from the rotor blade towards the annular gap.
Specific difficulties can occur during installation of the cover profiles. The surface of the rotor blade may possibly have irregularities so that gaps, which have to be sealed, occur between the cover profile and the rotor blade surface. This is usually carried out with a highly viscous sealing compound, which can only be used in a dry environment. Considerable problems occur if the rotor blade in the region of the rotor blade opening of the spinner is no longer circular-cylindrical but already merges into an aerodynamic profile of the rotor blade. If conventional cover profiles are installed on such a rotor blade, they deform so that their outer circumference is similarly no longer circular, as a result of which an optimum covering of the circular rotor blade opening of the spinner is no longer ensured.